1. Field of the Invention
The present invention relates to leveling instruments and more particularly to a device which can be used to check the accuracy of hand held levels.
2. Description of Related Art
Hand held levels have been used for many years to check the accuracy of vertical and horizontal surfaces. Such devices are essential instruments in the building trade. However, hand held levels can become inaccurate with age or may be manufactured improperly in the first place. Thus, if many workmen are at a particular project, each ones level may give a slightly different reading. If this occurs, it becomes impossible to determine which level is correct. Consequently, there has developed a need for a level checking device to determine the accuracy of such hand held levels.
U.S. Pat. No. 565,096 to Traut and U.S. Pat. No. 2,154,625 to Kleineschay show devices for repairing and correcting spirit levels. In the Traut device, the level being adjusted is turned end for end and the horizontal surface of the Traut device is adjusted each time the level is turned. The Kleineschay apparatus is adjusted to provide a level surface using an accurate level.
U.S. Pat. No. 2,373,641 to Ackerson shows a level having two pivotally connected members, the angle between which can be adjusted by a screw device.
U.S. Pat. No. 1,683,509 to Wescott shows another level having two pivotally connected elements, the angle between which can be adjusted by a screw mechanism.
U.S. Pat. No. 2,118,470 to Melvin shows a level device having mutually perpendicular surfaces so that both vertical and horizontal surfaces can be measured.
U.S. Pat. No. 787,940 to Perks shows another device having mutually perpendicular surfaces.